What actually differs
The Full and FOSS builds are the same GPS Setter module with different components underneath. The setting, hooking and location behaviour are shared. Only the map display and the fused location provider change.
Full uses Google Maps for the map and Google Play services for fused location. FOSS uses the MapLibre library for maps and microG for location, with no Google code involved at all.
Choose Full if your phone is a normal Google phone
If your phone shipped with the Play Store, Google Maps and Play services, the Full build is the natural fit. Its scope setup includes Play services, which is how most commercial apps receive their location.
Full is also the easier build to troubleshoot. Most guides, screenshots and forum answers assume Google services are present, so the steps you read will match the phone in your hand.
Tip: Work through this guide in order the first time. Most GPS Setter problems come from one skipped step early on, not from the step where the problem appears.
Choose FOSS if you removed Google services
De-Googled ROMs, microG setups and privacy-focused builds cannot use the Full build properly. Play services is either missing or replaced, so the FOSS build exists precisely for these phones.
FOSS is also a statement of preference. Every part of it, including its dependencies, is free and open-source software. For some owners that alone settles the choice, and the module works just as well.
Switching builds later
Switching is possible but not casual. Uninstall the current build, install the other APK, then repeat the enable and scope steps inside LSPosed before rebooting again.
Your saved favourites can travel with you. Export them from the old build first, then import the file into the new one, and your usual test locations are back in seconds.
One warning on versions: if an update changes the application ID, Android treats it as a different app. Uninstall the old one first, because settings do not move across automatically.
Download: GPS Setter itself is free from its LSPosed listing. Go to the download section for the file information and the external download button.
Related guides
How to Install GPS Setter with LSPosed: Step-by-Step
From APK to a working set location: enabling the module, choosing scope, and the reboot most people skip.
How to Set a Location with GPS Setter (System-Wide and Per App)
Dropping the pin is the easy part. This guide covers system-wide mode, per-app profiles, favourites and stopping cleanly.